The present invention relates to a fan system used in an electrophotographic apparatus such as a laser beam printer.
Conventionally, an electrophotographic printer has functional elements including at least a development unit for developing a latent image on a photoconductive drum, a transfer unit for transferring a toner image to a sheet, and a fixing unit, comprising a heat roller and a pressure roller, for fixing a toner image to a sheet. Additionally, an electrophotographic printer will conventionally have an electronic controller to control the described functional elements.
In the normal operation of the electrophotographic apparatus, some of the functional elements generate heat. Overheating of certain elements of the electrophotographic apparatus may damage those elements or other nearby parts. Thus, the apparatus will commonly have a cooling fan system to cool each of the heat-generating elements.
For example, the fixing unit commonly includes a heat roller and a pressure roller near each other. If the heat roller in the fixing unit overheats, a rubber layer covering the nearby pressure roller may deform. Furthermore, if the ambient temperature becomes high due to the heat roller, a sheet positioned near the fixing unit may also deform. The heat roller itself may suffer some damage. Therefore an individual cooling fan is often dedicated to cool the heat roller.
The electronic components in the controller also generate heat, and the controller is therefore also susceptible to damage from self-generated heat. Normally, an additional individual cooling fan is dedicated to cool the controller.
Additionally, an electrophotographic printer may have a system to remove ozone generated by the transfer unit. An ozone filter and a dedicated exhaust fan are commonly used to remove ozone.
Thus, a conventional electrophotographic printer is provided with several dedicated fans, each taking up space, consuming electrical current, generating noise, and having a certain cumulative part cost.